This section provides background information related to the present disclosure which is not necessarily prior art.
Toggle clamps are used for a variety of purposes, such as retaining and/or fixturing a work piece. A conventional toggle clamp comprises a clamp body that can be fastened to a work station or other supporting structure. A retaining arm is pivotally coupled to the clamp body to permit articulation of the retaining arm relative to the generally-stationary clamp body. A hold down member can extend from a distal end of the retaining arm and operably engage the work piece. A handle member is further pivotally coupled to the clamp body and operably engages the retaining arm to articulate the retaining arm between a raised and disengaged position (e.g. release position) and a lowered and engaged position (e.g. retaining position). The lowered and engaged position engaging the work piece to retain and/or fixture the work piece in position.
Conventional toggle clamps can include a variety of handles structures, including elongated members and the like, and a variety of configurations, including vertical or horizontal-handle Hold-Down style clamps. Conventional toggle clamps can further include push-pull, push-pull drawbar, hook, and latch type linear actuating clamps. Many of these configurations are offered in heavy duty configurations for some applications.
Generally, toggle clamps are a quick-acting mechanical linkage with three basic elements—an action, a linkage, and a handle or actuator. During operation, the clamp is first moved into position to contact the work piece and then actuated to apply a clamping force. This clamping force is generated by compressing or stretching the linkage elements.
In some cases, conventional toggle clamps can include a locking mechanism. In conventional toggle clamps, the locking mechanism can be engaged by moving a center pivot of the toggle action past the centerline of two other pivots, against a stop. The lock achieved by the movement of the center pivot past centerline is referred to as the “toggle lock.” However, conventional toggle locks have at least two primary disadvantages. The first disadvantage is that heavy vibration or impact can cause the center pivot to move from its past center position and, thus, “unlock” the mechanism. The second disadvantage, and potentially more prevalent, is that the clamp can be inadvertently actuated by inadvertent contact with the actuator.
For these and other reasons, some toggle clamps include a secondary locking mechanism that must be activated before the clamp mechanism itself can be actuated. The vast majority of these secondary locking mechanisms fall into two categories. The first involves the base clamp components remaining essentially unchanged from its typical configuration and the secondary locking mechanism being simply added on in some way that restricts normal operation of the clamp until it has been activated. In the second, some of the clamps primary components have been altered from the base model, but the lock functions via a wedging or jamming action as opposed to a true locking action. In some applications, these locking mechanisms, or secondary locks, must be actuated in a clumsy or awkward action by the operator.
Although this arrangement may be useful for some applications, it has been found that they often fail to provide a simple and consistent locking method. In fact, in many cases, these conventional secondary locking mechanisms are less reliable and can be overcome with moderate force. Frequently they require the operator to activate them though a clumsy or awkward action that cannot be integrated into the normal and deliberate clamp activation. For example, if the clamp is normally activated by a left to right motion of the operators hand along the linear axis of the clamp, the secondary locking mechanism may require a pushing or pulling motion perpendicular to the long axis before the primary activation motion can be initiated. In many cases, they only allow the clamp to be locked in a single position, usually closed.
Accordingly, there exists a need in the relevant art to provide a toggle clamp that overcomes the deficiencies of conventional toggle clamp designs. Moreover, there exists a need in the relevant art to provide a toggle clamp that provides a suitable, robust locking mechanism that can retain the handle member and/or retaining arm in both a release and retaining position.